Production of cellulose nitro-acylate



Patented Oct. 25, 19321 UNITED STATES;

caries] CYRIL J. STAUD, OF ROCHESTER, NEW YORK, AND. CHARLES E..WABING, DAY'LBOK OHIO, ASSIGNOBS T0 EASTMAN, KODAK. COMPANY, OF. ROCHESTER; NEW YDRK, A. CORR PORATION-VOF .YORK

rnonuc'nonror cnnnnmsn unite-Amara N'o Drawing.

This invention relates to a: process ofpreparing cellulose nitro-acylate by nitrating the cellulose after the stepsrof aeylation and.

hydrolysis, by the use of fuming nitric. acid.

5 or an. oxide ofnitrogen atter rendering'the hydrolyzed dope; anhydrousquantities: of nitrogen. were present by initially nitrating the cellulose with. nitric and sulphuric acids before the: acylation. Cel- 1'6 lulose nitro-acylates have alsobeen produced by simultaneously nitrating and acylating' the cellulose in the acylation bathby adding nitric acid; shortly after theaddition of the acylatingagent to the pre-treatedcotton linters and: before a satisfactory dope has been obtained. Howcver no process has previously beendisclosed which teaches the substantial addition of nitrogento the cellulose subsequent to the acylation and hydrolysisof the same as is disclosed herein. I

Another object'ofthe invention is the production of a cellulose nitro-acylate which has certain very desirableproperties. The most' remarkable of these characteristics is the solubility of the product of our processin a great variety of organic solvents. We have found, that the mixed esters resulting from this process are-soluble in acetone; chloroform, ethylene dichloride, ethyl acetate, ethyl lactate, 1.4 dioxan and pyridine.

' Another object of our invention isto providea process that can-be carried out under ordinary temperature conditions. This is'in contrast to the processes where simultaneous nitration and acylation are carried out,

in whichthereis acertain element ofhaza-rd dueto the use ofcertain nitratingagentsat elevated temperatures; which may'blow out workmen. Also these limitedtemperatures lead to better working conditions. for the operators.

Although it that. the use of nitric. acid in the hydrolysis and damage apparatus and possibly injure hasbeen known for a long time i Application med; December 31, 1930. Serial No. 505,960.

of cellulose acetate gave beneficial results, neverthelessonly negligible: quantities of; ni

trogen. have thereby beenfintroduced. into the.

celluloseacetat'e, for instance,,when cellulose tr-iacetate wasdissolvediin'-70%"nitrienaeid, or;

when nitric'acid was addediftm cellulose: triacetatexinv the acetylation' mixture. negligibleamounts: of nitrogen is: meant less than .01.%.

We have found that although 98% filming" nitric acid-{may be-added at the close of liy drolysis in; a greater concentration than. USU;- ally used for nitration, nevertheless; when the dope is not dehydrated no appreciable amount of nitrogen is introduced after six: teen hours contact with the cellulose acetate dope at room temperature. We. havetoundi however that if hydrolyzed! cellulose acetate,

in! dope form-,, 15 made substantially anhye drous; tlie ad'diti'on of fuming;nitric;acid or liquidnitrogen dioxide (N0 will introduce; appreciable. quantities of nitrogen into the: celluloseiesten at.. ordinary temperatures; Ii: thedope afterv hydrolysis is to be rendered anhydrous, acetic anhydnide or some other suitable dehydrating agent may be; addedin amounts sutficientltdcombine" with practicalliy all the water-presentto-"fomiacetic acid.

Other suitabledehydrating materials suchas:P B 05, S0 or-fatty acid anhydrides' or the like may be used. It ispreferred,how-- ever, to use the anhydride ofthe fatty'acids. corresponding to theacyl group of the cellulose acylate of the dope. The term.nitrating.; agent? asv used in this. application refers to fuming; nitric: acid, NO or" its dimer; N 94, N 05 or-N Og.

an illustration of thecarrying out of this process, we give the following examples:

I Ewample'l' About 100- lbs: ofacetic anhydride 85 preferred) werefadded to about 400 15s;

of acetic acid cellulose acetate dope, containing about" 12% total solids. After? then, ough mixing the temperature began to use" due to the heat liberated by the hydrolysis of the acetic anhydride. The dope was cooled to about 25 C. and about 60 lbs. of fuming nitric acid (about 98%) or liquid nitrogen dioxide was added. The temperature then started to rise, but was brought back to about room temperature by means of ice cooling. The material was then allowed to stand at 2025 C. for fifteen totwenty hours, or until the reaction was completed, after which it was precipitated, washed and dried in the usual manner, as well known in the art. Analysis showed that the material contained about .16% nitrogen.

Ewample I].

About 25 lbs. of finished hydrolyzed acetic acid dope was placed in a small mixer and cooled to about 60 F. and 68 lbs. of acetic anhydride were added. The temperature increased to 90 F. -After cooling to about F., about 500 c. c. of fuming nitric acid (98% preferred) or liquid nitrogen dioxide was added in small portions. The temperaturerose to about 120 F. The jacket temperature was kept around 40 F. untilt-he inside temperature dropped to about70 to F. The outside temperature was then raised to F. and held for from 5 to 8 hours, or until the reaction was complete, after which the material was precipitated, washed and dried in the usual manner. The product was found to contain about 24% nitrogen.

- As the acetates are the most economical and most used of the fatty acid derivatives at the present time, the cellulose acetate dope is the preferred material. However, the dope of propionic, butyric, lauric, crotonic, etc., acids may be used. In that case the anhydride used for dehydrating may be preferably that corresponding to the. acid of the dope.

It isapparent that the essential feature of our invention is the treating of a dry cellulose acylate dope which has been subjected to a hydrolysis treatment, with a nitrating agent containing an oxide of nitrogen in ap. preciable amount. a

The solvent which is contained in the dope, the amount of hydrolysis, the dehydrating agent, temperatures and times of treatment may obviously be varied as desired the only limiting condition being that the variations are compatible with, the practice of this invention. Also a mixture of the nitrating agents or of the dehydrating agents may be i used where just one of these materials is called for, withoutaflecting detrimentally the operation of this process.

at we now claim as our invention and desire to secure. by Letters Patent of the United States is: i

1. In the process of making cellulose nitroacylate the step which comprises nitrating an anhydrous partially de-esterifiedcellulose acylate.

2. In the process of making cellulose nitroacylate the step which comprises treating a partially de-esterified acylated cellulose in an anhydrous solution with a nitrating agent.

3. In the process of making cellulose nitroacylate, the step which comprises treating partially de-esterified cellulose acylate in solution in an anhydrous hydrolysis bath with a nitrating agent.

4. The step of nitrating a partially de-esterified cellulose acylate which comprises treating it in an anhydrous hydrolysis bath with a nitrogen compound selected from the group consisting of fuming nitric acid, N0

or N 0 N 0 and N 0 5. The process of making cellulose nitroacetate which comprises dehydrating a hy drolyzed cellulose acetate dope with an acid anhydride and then nitrating the hydrolyzed cellulose acetate before it is precipitated.

6. The process of making cellulose nitroacylate which comprises dehydrating hydrolyzed cellulose acylate dope with an acid anhydride selected from the group consisting of P 0 S0 B 0 and acetic, propionic, butyric,.lauric and crotonic anhydrides, and then treating the de-esterified cellulose acylate with a nitrating agent.

7. A process of making cellulose nitroacylate which comprises acylating cellulose, hydrolyzing the cellulose acylate formed, dehydrating the. hydrolysis bath with an acid anhydride and nitrating the cellulose acylate contained therein.

8. The process of making cellulose nitroacylate which comprises dehydrating a hydrolyzed cellulose acylate dope with a fatty acid anhydride and then nitrating the dehydrated cellulose acylate dope with fuming nitric acid. a

9. The process of making cellulose nitroacylate which comprises dehydrating a hydrolyzed cellulose acylate dope with a fatty acid anhydride'and then nitrating the dehydrated cellulose acylate dope Wth nitrogen tetroxide.

10. In the process of making cellulose nitroacetate, the step which comprises nitrating an anhydrous partially de-esterified cellulose acetate.

11. In the process of making cellulose nitroacetate the step which comprises dehydrating hydrolyzed cellulose acetate dope with an acid anhydride.

12. In the process of making cellulose nitroacetate the step which comprises dehydrating a partially de-esterified cellulose acetate dope with an acid anhydride selected from the group consisting of P O S0 B 0 and acetic, propionic, butyric, lauric and crotonic anhydrides.

13. In the process of making cellulose nitroaceta-te, the step which comprises nitrating an anhydrous partially de-esterified cellulose acetate dope with a nitrating agent selected from the group consisting of fumingnitric,

acid, N0 or N 0 N 0 and N 0 Signed at Rochester, N. Y. this December 1930.

Signed at Dayton, Ohio, this 26th day of December 1930.

CHARLES E. WARING. 

